Last updated: June 16, 2026
For years I assumed feeding horses was straightforward — hay, grain, water, and the occasional treat. Then I started managing racehorses alongside broodmares, easy keepers, and hard keepers, and realized something important: two horses standing side by side can need completely different diets. What horses eat depends on age, workload, health status, and access to quality forage. But one rule never changes. Horses are designed to live on grass and fibrous plants, not large grain meals. Most feeding problems I see — colic, ulcers, obesity, laminitis — begin when that basic principle gets ignored.
This guide explains what horses eat, how much forage they need, when grain makes sense, which foods are safe as treats, and the feeding mistakes that cause the most problems.
- Forage is the foundation. Quality hay or pasture should form the base of every horse’s diet — roughly 1.5–2% of body weight in forage per day, regardless of workload
- Grains and concentrates supplement forage; they don’t replace it. Working horses may need concentrated energy, but large grain meals without adequate forage cause digestive problems
- Water access is non-negotiable. Horses need 5–10 gallons of clean, fresh water daily — more in heat or during heavy work. Dehydration leads directly to impaction colic
- Nutritional needs vary by age, workload, and health status. Foals, seniors, broodmares, and performance horses each have different requirements
- Some foods are genuinely dangerous. Nightshades, onions, garlic, and high-sugar items like candy can cause serious harm
About this guide: Feeding principles are drawn from the Merck Veterinary Manual, Rutgers Equine Science Center, University of Minnesota Extension, and hands-on barn experience. For questions about a specific horse’s diet, consult your equine veterinarian or nutritionist.
Going deeper: For how horses actually digest food, see our horse digestion guide. For racehorse-specific protocols — starch limits, energy calculations, race-day feeding — see our racehorse nutrition guide. For vitamins, minerals, and micronutrients, see our vitamins and minerals guide.
Table of Contents
What Do Horses Eat? The Foundation
Horses are hindgut fermenters — their cecum and large colon house billions of bacteria that break down fibrous plant material into volatile fatty acids, supplying up to 70% of daily energy. The entire digestive system is optimized for continuous, low-volume intake of fiber-rich food over 16–18 hours per day. When that’s compressed into two or three large, grain-heavy meals, conditions for colic, ulcers, and metabolic problems follow.
The foundation of every horse’s diet is high-quality forage — at least 1.5–2% of body weight daily, roughly 16–22 pounds for a 1,100-pound horse. Everything else builds on that base. Horses without adequate forage access are at elevated risk for gastric ulcers, colic, and behavioral problems from digestive discomfort.
What Do Horses Eat in the Wild?
Wild horses graze for 16–18 hours per day, moving constantly and covering significant ground to find what they need. Their natural diet is overwhelmingly grasses — Timothy, Bermuda, fescue, bluegrass, and native prairie varieties depending on region and season — supplemented with shrubs, plants, tree bark, and occasional fruits or berries when available. The nutritional profile varies significantly by season: spring and summer grass is rich in non-structural carbohydrates and protein, while winter forage is drier, lower in energy, and often supplemented naturally by browsing on woody plants and bark.
What this natural pattern tells us about how to feed domesticated horses is more important than the specific plant list. Wild horses eat small amounts continuously — not large boluses twice a day. They eat high-fiber, relatively low-starch food, not grain-heavy diets. They drink from natural water sources as needed throughout the day. And they move while they eat, which keeps their gut motility active and reduces the risk of impaction. Domesticated horses live in stalls, eat at scheduled times, and rarely move enough to replicate this. The best feeding programs try to close that gap — consistent forage access, small grain meals if needed, free-choice salt and water, and as much turnout as practical.
Hay: The Most Important Feed
For most domesticated horses, hay is the primary feed — it replaces or supplements pasture when grazing isn’t available, which for many horses is most of the year. Choosing the right type of hay matters as much as the quantity. The main categories:
| Hay type | Protein | Energy level | Best suited for | Notes |
|---|---|---|---|---|
| Grass hay (Timothy, Bermuda, orchard grass, fescue) | 8–12% | Moderate | Mature horses, easy keepers, idle horses | High fiber, lower calorie density — ideal foundation hay for most horses |
| Legume hay (Alfalfa, clover) | 15–22% | High | Hard-working horses, growing foals, lactating mares, underweight horses | Rich in calcium and protein — too rich for easy keepers or idle horses alone |
| Mixed hay (grass + legume blend) | 10–15% | Moderate–High | Most horses; good all-purpose option | Balances the fiber of grass with the protein and energy of legumes |
| Bermudagrass / Alicia (warm-season grasses) | 8–12% | Moderate | Horses that don’t need high protein — common in Gulf Coast states | Monitor NSC in spring growth; mold risk in humid storage climates |
Always feed hay before grain at every meal — chewing hay produces saliva that buffers stomach acid, and having forage in the stomach slows grain passage through the digestive tract, improving starch absorption and reducing digestive risk. Store hay elevated and ventilated; mold develops quickly in humid climates and can cause serious digestive and respiratory problems. Inspect each bale before feeding.
One of my mares wasn’t doing well on mixed hay — her coat was dull, her energy flat. I switched her to high-quality alfalfa, and within two weeks her coat developed real gloss and her energy improved noticeably. Not every horse thrives on the same hay. Pay attention to body condition and coat quality as signals that the current hay isn’t meeting the horse’s needs.
Fresh Pasture and Natural Grazing
Fresh pasture is nutritionally superior to hay — it retains water-soluble vitamins, has higher digestibility, and provides the constant low-volume intake the equine digestive system was designed for. Horses with access to quality pasture are generally healthier, calmer, and require less supplementation than stall-kept horses on hay alone. Common pasture grasses include Kentucky bluegrass, Bermuda, Timothy, fescue, and orchard grass, with nutritional content varying by species, season, and management.
The key to maintaining good pasture is rotational grazing — dividing turnout areas into sections and rotating horses between them. A few years ago I noticed sections of my pasture were overgrazed while others went untouched. Rotating between paddocks allowed overgrazed areas to recover, kept the horses on consistently fresh forage, and improved coat quality and energy levels noticeably across the barn.
Two important cautions. First, spring pasture: new spring growth is high in non-structural carbohydrates (NSC) and can trigger laminitis in metabolically sensitive horses. Introduce spring pasture gradually — start with 30 minutes per day and increase over two to three weeks. Second, fresh lawn clippings: never feed cut grass clippings. They ferment rapidly in a bucket or pile, producing heat and bacteria that can cause serious colic when consumed in quantity.
Grains, Pellets, and Commercial Feeds
Grains and commercial feeds provide concentrated energy that forage alone can’t deliver for horses with high caloric demands — actively competing horses, hard keepers, growing foals, and lactating mares. The key is keeping grain amounts in proportion to forage and limiting the amount per meal. The small intestine can only absorb a certain amount of starch per feeding; excess starch reaches the hindgut, where it ferments rapidly and disrupts microbial balance.
Common grain options: oats are the traditional racehorse grain — highly palatable, relatively easy to digest, and safe when not overfed. Corn provides more energy per pound but is lower in fiber and must be cracked or rolled for digestibility. Barley is between the two and also requires processing. Processing grains — rolling, cracking, or extruding — breaks down seed coats and improves small intestine absorption, which reduces the risk of starch reaching the hindgut undigested.
Commercial pelleted feeds and complete feeds offer a consistent nutrient profile that simplifies rationing. Textured or sweet feeds are palatable but often high in sugar — useful for getting a picky eater interested, but not ideal as a dietary foundation. Complete feeds can replace hay entirely for horses with severe dental problems, though they lack the chewing benefit of long-stem forage. Pellets and beet pulp are useful hay alternatives when quality forage is unavailable.
Miles’s Take — the grain overload I watched cost a barn manager thousands: I knew a barn manager who fed her horses 8 pounds of sweet feed twice daily because she figured more energy meant better performance. Within three months, two horses had laminitis, one had recurring colic, and all of them showed signs of gastric discomfort — grinding teeth, girthiness, dropping feed. Her vet cut grain to 3 pounds per meal, increased forage, and the problems resolved. I’ve made smaller versions of the same mistake myself. With one of my younger horses in training, I increased grain thinking it would fuel harder work. She developed mild colic and became lethargic. Scaled back the grain, prioritized high-quality hay, and she came right. Grain supplements the diet; it doesn’t replace forage.
What Should Horses Eat Every Day?
The answer varies by horse, but the framework is consistent. Every horse, regardless of workload, needs these four things daily: quality forage, clean water, free-choice salt, and consistent feeding times. Everything else — grain, supplements, special feeds — is added based on the individual horse’s needs.
| Horse type | Forage | Grain / concentrates | Key consideration |
|---|---|---|---|
| Idle / light work (1–2 hrs/day) | Free-choice good grass hay; 1.5–2% BW daily | Usually none needed; small amount if hard to maintain weight | Overfeeding grain to an idle horse causes obesity and metabolic problems |
| Moderate work (2–4 hrs/day) | Quality hay or mixed hay; 1.5–2% BW daily | 1–4 lbs grain per meal, split across 2–3 feedings | Match grain to actual workload; adjust weekly based on body condition |
| Hard work / performance / racing | High-quality hay — alfalfa blend; never below 1.5% BW | 4–8 lbs/day split across 3+ meals; max 4–5 lbs per meal | Fat supplementation (oil, rice bran) adds calories without starch risk |
| Easy keeper / overweight | Grass hay only; restrict to 1.5% BW; use slow-feeder | None, or minimal ration balancer for micronutrients | Limit pasture access; avoid alfalfa and sweet feed |
| Hard keeper / underweight | Free-choice high-quality hay; alfalfa to increase calories | Increase grain gradually; add fat supplement | Rule out dental and parasite issues first — weight loss despite adequate feed often has an underlying cause |
| Senior horse | Soaked hay cubes, senior pellets, or chopped hay if dental issues prevent chewing long-stem | Senior complete feed if hay intake is compromised | Annual dental exams are essential; poor dentition is the most common reason seniors lose weight |
| Pregnant / lactating mare | High-quality mixed hay; alfalfa for lactation | Increase in last trimester; peak demand during lactation | Calcium needs double during lactation — alfalfa helps; monitor for over-condition in pregnancy |
Nutrient Requirements by Horse Type
A horse’s nutritional needs change significantly with age, workload, reproductive status, and health. The table below provides minimum daily nutritional targets as a starting reference — individual horses require adjustment based on body condition, workload response, and veterinary guidance.
| Horse type | Crude protein (% of ration) | Energy (Mcal/day est.) | Calcium (g/day) | Phosphorus (g/day) | Vitamin A (IU/day) |
|---|---|---|---|---|---|
| Mature horse at rest (900–1,100 lbs) | 10% | 14–16 | 16–20 | 12–15 | 10,000–12,500 |
| Mature at light work (1–3 hrs/day) | 10% | 18–22 | 16–20 | 12–15 | 10,000–12,500 |
| Mature at moderate work | 10% | 24–29 | 17–21 | 13–16 | 10,000–12,500 |
| Mare — last 90 days of pregnancy | 11.5% | 15–17 | 20–24 | 15–18 | 20,000–25,000 |
| Lactating mare | 13.3%+ | 24–28 | 42–47 | 36–39 | 20,000–25,000 |
| Foal (3 months) | 19% | ~12 | 31 | 19 | 4,400 |
| Weanling (6 months) | 14.3% | ~15 | 46 | 29 | 9,000 |
| Yearling | 12.3% | ~17 | 26 | 17 | 11,000 |
| 18-month-old | 11.3% | ~17 | 23 | 16 | 16,000 |
Units note: calcium and phosphorus are expressed in grams per day, following Oklahoma State University mineral guidelines; Vitamin A in international units (IU); energy in Mcal/day. All values are minimum daily requirements — individual horses should be assessed against these baselines and adjusted under veterinary guidance. A few notes on how to read and use this table. Lactating mares need dramatically more protein and calcium because milk production makes enormous demands on both — a mare in peak lactation is essentially eating for two. Young foals need relatively high protein and minerals because bone and muscle development is happening rapidly in the first months of life. Always weigh grain rather than measure by volume scoop — different feeds have different densities, and a “scoop” of oats weighs considerably less than a scoop of corn. Introduce any new feeding plan gradually over 7–14 days.
Special dietary situations worth noting: horses with laminitis should avoid high-carbohydrate feeds and have restricted access to lush pastures, particularly in spring. Horses with Equine Metabolic Syndrome benefit from low-starch, low-sugar diets and controlled grazing. Senior horses with dental issues often need softened feeds — soaked hay cubes, pellets, or complete senior feed — as chewing long-stem hay becomes painful or inefficient. For detailed performance horse nutrition protocols, consult your equine veterinarian or see the specialist guides linked in the reading section below.
Common Feeding Mistakes to Avoid
Six feeding mistakes that cause the most problems:
- Irregular feeding times. Horses thrive on routine. Inconsistent schedules disrupt gut motility, increase acid exposure, and elevate colic risk. Feed at the same times daily
- Abrupt diet changes. The hindgut microbiome needs 7–14 days to adapt to new hay types, grain blends, or pasture access. Sudden changes cause fermentation imbalances — colic, loose manure, or worse
- Overfeeding grain. Excessive grain overloads the small intestine, pushing undigested starch into the hindgut where it acidifies and causes microbial collapse. Keep grain meals under 4–5 lbs for an average-sized horse
- Insufficient water access. Dehydration is the leading cause of impaction colic. Horses need 5–10 gallons of clean, fresh water daily — more in heat or during hard work
- Not adjusting diet for workload. An idle horse being fed like a racehorse gains weight and develops metabolic problems. A hard-working horse underfed on energy underperforms and loses condition. Adjust feed to actual workload
- Neglecting dental care. Poor dentition means poor chewing, which means larger feed particles reaching the stomach and hindgut. Annual dental exams and floating when needed protect the first step in the entire digestive process
Foods Horses Should Not Eat
Not everything edible for humans is safe for horses. A few categories cause serious harm and are worth knowing before anyone in the barn offers treats without checking first.
Dangerous foods to avoid: caffeine and chocolate can cause severe cardiac reactions. Nightshade family plants — tomatoes, potatoes, their leaves and stems — cause colic and longer-term damage. Onions and garlic in significant quantities cause hemolytic anemia that can be life-threatening. Brassica vegetables (kale, broccoli, cabbage, turnips) produce painful gas fermentation in the hindgut. Moldy or contaminated feed of any kind produces mycotoxins that disrupt fermentation and reduce appetite — always inspect hay and grain before feeding.
Safe treats in moderation: Apples and carrots are the classic choices for good reason — horses accept them readily and they’re nutritionally benign in small amounts. Watermelon (including the rind, cut into manageable pieces) is safe and hydrating. Bananas, pears, and pineapple are also generally safe. The principle is moderation and no surprises — introduce any new treat gradually and don’t feed items that could lodge in the throat whole.
Key Takeaways — What Do Horses Eat
- Forage is the only non-negotiable. Every other feeding decision — grain type, supplement, commercial feed — only matters if adequate forage is already in place
- Feed hay before grain at every meal. Chewing hay produces saliva that buffers stomach acid and slows grain passage through the gut, protecting against ulcers and starch overload
- Grain supplements energy; it doesn’t replace forage. Large grain meals without adequate hay cause the digestive problems — colic, ulcers, laminitis, hindgut acidosis — that most horse owners eventually encounter
- Water is non-negotiable. 5–10 gallons daily, clean and fresh, available at all times. Dehydration leads directly to impaction colic
- Nutritional needs change with age and workload. Foals, seniors, lactating mares, and hard-working horses each need different feed profiles — adjust diet to the actual horse in front of you, not a general template
- Consistency prevents most feeding problems. Same times, same forage, gradual transitions for any feed changes — the horse that gets managed the same way every day is the horse that rarely needs emergency veterinary calls
Frequently Asked Questions
How much hay does a horse need per day?
Most horses need 1.5–2% of their body weight in forage daily. For a 1,100-pound horse, that’s roughly 16–22 pounds of hay per day. Horses with higher energy demands (hard work, lactation, cold weather) may need more. Hay should be available throughout the day rather than in two large feedings — long gaps between forage access increase ulcer risk and digestive stress.
Do horses need grain every day?
Not necessarily. Many horses in light work or maintenance can meet their caloric needs on quality forage alone. Grain becomes necessary when a horse’s energy demands exceed what hay and pasture can provide — hard-working horses, growing foals, lactating mares, and underweight horses are the most common cases. If a horse is maintaining good body condition on forage, adding grain may cause more problems than it solves.
Do horses eat meat?
No. Horses are strict herbivores — their digestive system is built entirely around processing plant material. They lack the stomach acid concentration, enzymes, and intestinal anatomy to digest animal protein. Occasionally a horse will accidentally ingest small amounts of something non-plant (a bird egg, an insect), but this is incidental and not nutritionally significant.
How do you transition a horse from pasture to hay?
Gradually, over 7–14 days minimum. Start by replacing about 25% of pasture time with hay access, then increase the hay proportion over the following days. The hindgut microbiome needs time to adapt to the different fiber composition of hay versus fresh grass. Abrupt transitions — moving directly from full pasture to hay-only — frequently cause loose manure, colic, or both.
What are the best feeding tips for senior horses?
Senior horses often need more digestible feeds as dental function and metabolic efficiency decline. Options include soaked hay cubes, senior complete feeds, beet pulp, and alfalfa pellets. If a senior horse is losing weight despite adequate-seeming intake, the first step is a dental exam — poor dentition is the most common underlying cause. Senior horses also benefit from smaller, more frequent meals and consistent forage access.
About Miles Henry
Racehorse Owner & Author | 30+ Years in Thoroughbred Racing
Miles Henry (legal name: William Bradley) is a professional horseman based in Folsom, Louisiana. He holds Louisiana Racing License #67012 and has spent over three decades managing Thoroughbreds at premier tracks including Fair Grounds, Delta Downs, and Evangeline Downs.
Expertise & Hands-On Experience: Beyond the track, Miles has decades of experience in specialized equine care, covering everything from hoof health and nutrition to training protocols for Quarter Horses, Friesians, and Paints. Every guide on Horse Racing Sense is rooted in this “boots-on-the-ground” perspective.
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